The invention pertains to a device for splicing webs, in particular, paper webs for manufacturing corrugated cardboard, as well as a device for manufacturing corrugated cardboard by gluing together at least two webs with such a splicing device.
In known splicing devices as described, for example, in EP-B-0 453 727, a web unrolling device which consists of a stand that can be mounted on the floor and contains two lateral carrying arms for each web roll is assigned to the splicing device. The paper web in question is unrolled from the respectively active web roll. The paper web is transported through the splicing device which, except during the splicing process, is inactive and then transported to additional processing stations. When the end of the respectively active web roll is reached or a splicing process is necessary for different reasons, e.g., due to a format or quality change, the paper web of the active web roll is cut off in the splicing device and connected (spliced) to the front end of the paper web of the respectively other web roll which was prepared in the required fashion. In this case, the front end of the paper web to be spliced is inserted into the splicing device, preferably while the active web roll is still being processed, whereafter the front end of the paper web is cleanly cut off and provided with a (double-sided) adhesive tape. The splicing device is usually realized in such a way that it contains a web reservoir which makes it possible to store such a length of the active web, the end of which is almost reached, that the time required for cutting the initially active paper web and connecting the rear end of this paper web to the already prepared front end of the paper web to be spliced can be bridged. A continuous operation of the system for additionally processing the paper web in question can be ensured in this fashion.
If necessary, the tube on which the previously active paper web was wound, or the rest of this paper roll can be removed from the respective lateral carrying arm of the web unrolling device and replaced with a new web roll that, if necessary, may also have a different quality or width.
The removal of the winding tube or the depleted web roll from the respective carrying arm and its replacement with a new web roll is a relatively time-consuming process. The production time, within which a constant format or a constant quality is produced, may be shorter than the time required for the removal of one web roll and its replacement with a new web roll, in particular, in corrugated cardboard systems, in which frequent format and/or quality changes are necessary. In known splicing devices, this results in standstill times that, in turn, have negative effects on the productivity of the entire system.
This is the reason why web unrolling devices or web feeders were developed which allow an exchange of the web roll within the shortest possible time. A device of this type is, for example, described in DE-A-39 12 328.
However, the measures disclosed in DE-A-39 12 328 only make it possible to reduce the time for replacing the web roll on the respective carrying arm to a certain degree. In certain systems, in particular, special systems for processing very small orders, this time may still be excessively long for ensuring an optimal productivity of the entire system.
Based on this state of the art, the invention aims to develop a device for splicing webs, in particular, paper webs for manufacturing corrugated cardboard which also ensures an optimal productivity of the entire system into which the splicing device is integrated, when processing very small orders. Another objective of the invention consists of developing a device for manufacturing corrugated cardboard by gluing together at least two webs, into which device such a splicing device is advantageously integrated.
The invention starts from the recognition that the productivity of a system for processing webs, e.g., a corrugated cardboard system, in which splicing processes must be carried out within relatively short intervals, can be significantly increased if a conventional splicing device with two intakes for the webs to be spliced contains a web unrolling device that is able to accommodate at least three web rolls. Due to this measure, it is possible to unroll the respectively active web (i.e., the web currently being processed by the system) from a first web roll that is held in the web unrolling device and transport this web to the additional system via the splicing device. The front end of a second web that is held in the web unrolling device can already be prepared for the next splicing process, transported to the respectively other intake of the splicing device and held therein until the next splicing process is carried out. If so required, an exchange of the web roll in question may already take place in the third position of the web unrolling device such that, in theory, the front end of this third web can be transported to the intake of the splicing device which has become available after the splicing process was carried out (i.e., the intake, through which the respectively active web was supplied before the splicing process was carried out) immediately after the splicing process of the two webs that are simultaneously supplied to the splicing device has taken place. Consequently, the time between two splicing processes can be reduced to a minimum which is defined by the preparation and insertion of the front end of the web to be spliced. Due to the additionally provided stand-by web roll, this time is not dependent on the time required for exchanging this web roll.
According to one embodiment, the web unrolling device may be constructed in such a way that the web of a web roll can, depending on the respective requirements, be transported to either of the two intakes of the splicing device. This provides the advantage that the shortest possible time for a splicing process can be achieved in any case, independently of the web rolls from which the webs to be spliced are supplied to the splicing device.
In this case, it is usually necessary to provide one or more deflection rollers for transporting the respective web to one or the other intake of the splicing device. The seating positions of the web rolls in the web unrolling device may lie vertically on top of one another, preferably centrally with respect to the horizontal orientation of the splicing device. Although this results in a relatively large structural height, only a minimal quantity of deflection rollers or, in the most favorable instance, no deflection rollers at all, are required for transporting a web from any of the three web roll positions to either of the two intakes.
According to another embodiment of the invention, the transport of the webs to the splicing device may take place in such a way that the webs of both web rolls which are situated in two given positions of the web unrolling device can be alternately transported to only one of the two intakes of the splicing device. This simplifies the design of the web unrolling device. Only a minimal quantity of deflection rollers or no deflection rollers at all are required for transporting the webs to the intakes of the splicing device. In particular, it is possible to utilize conventional web unrolling devices that are able to accommodate only two web rolls. In contrast to known splicing devices, such a conventional web unrolling device is, however, only assigned to one intake of the splicing device.
Another option consists of utilizing a conventional splicing device with a conventional web unrolling device that has two web roll positions, with each position of the conventional web unrolling device being respectively assigned to one intake of the splicing device, and with one additional unrolling unit for accommodating an additional web roll being assigned to one or both intakes of the splicing device.
As mentioned previously, it would naturally also be possible to assign two positions for web rolls of the entire web unrolling device to each of the two intakes or only one. If this is realized for only one of the two intakes, a xe2x80x9cfast splicing processxe2x80x9d is only possible on one of the two sides of the splicing device.
A device for manufacturing corrugated cardboard by gluing together at least two webs may be realized in such a way that a splicing device of the previously described type is assigned to each of the two webs to be glued together.
The device for manufacturing corrugated cardboard may, for example, be realized in such a way that conventional splicing devices with one respective web unrolling device for two web rolls are utilized, with another conventional web unrolling device with two positions for two web rolls being provided between the splicing devices that are preferably arranged horizontally adjacent to one another. Each of the two positions can then be assigned to the respectively adjacent splicing device or to the adjacent intake of the respective splicing device.
These and other objects, advantages, and features of the invention will be apparent from the following description of the preferred embodiments, considered along with the accompanying drawings.